99 research outputs found
Divergent functional traits in three sympatric Arctic charr Salvelinus alpinus morphs are not coupled with the age of the lineage divergence
Three genetically discrete morphs of Arctic charr in Loch Rannoch, Scotland originated from a recent divergence within the lake (in situ) (piscivore and benthivore morphs) and from secondary contact of two older lineages (ex situ; a planktivoreâpiscivore/benthivore divergence). To test if the expression of traits with strong functional roles was linked to the age of the divergence, fin and gill anatomy, and dentition were quantified and compared across morphs. Five additional working hypotheses suggesting a rank order of trait expression amongst morphs were also tested. The planktivorous morph had more rays in the dorsal and pectoral fins, longer gill rakers (but not more) as well as a smaller gill cavity than the other two morphs. The piscivorous morph had more palatine teeth and longer teeth on the mandible, pre-maxillary and glossohyal bones, and a larger buccal cavity. These differences indicate a differential response to selection in these functional anatomical features most likely related to morph foraging specialisms. Notably, between-morph divergences in the expression of these traits were not simply linked to the length of divergence between morphs and have arisen equally quickly in the recent (in situ) divergence as they have in older, ex situ divergences
Weed control in soybeans
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Temporal stability of polymorphic Arctic charr parasite communities reflects sustained divergent trophic niches
Polymorphic Arctic charr Salvelinus alpinus populations frequently display distinct differences in habitat use, diet, and parasite communities. Changes to the relative species densities and composition of the wider fish community have the potential to alter the habitat niche of sympatric Arctic charr populations. This study evaluated the temporal stability of the parasite community, diet, and stable isotopes (ÎŽ13C, ÎŽ15N) of three sympatric Arctic charr morphs (piscivore, benthivore, and planktivore) from Loch Rannoch, Scotland, in relation to changes to the fish community. All Arctic charr morphs displayed distinct differences in parasite communities, diet, and stable isotope signatures over time, despite the establishment of four new trophically transmitted parasite taxa, and increased fish and zooplankton consumption by the piscivorous and planktivore morphs, respectively. Native parasite prevalence also increased in all Arctic charr morphs. Overall, Loch Rannoch polymorphic Arctic charr morph populations have maintained their distinct trophic niches and parasite communities through time despite changes in the fish community. This result indicates that re-stocking a native fish species has the potential to induce shifts in the parasite community and diet of Arctic charr morphs
Centile charts for birthweight for gestational age for Scottish singleton births
<p>Abstract</p> <p>Background</p> <p>Centile charts of birthweight for gestational age are used to identify low birthweight babies. The charts currently used in Scotland are based on data from the 1970s and require updating given changes in birthweight and in the measurement of gestational age since then.</p> <p>Methods</p> <p>Routinely collected data of 100,133 singleton births occurring in Scotland from 1998â2003 were used to construct new centile charts using the LMS method.</p> <p>Results</p> <p>Centile charts for birthweight for sex and parity groupings were constructed for singleton birth and compared to existing charts used in Scottish hospitals.</p> <p>Conclusion</p> <p>Mean birthweight has been shown to have increased over recent decades. The differences shown between the new and currently used centiles confirm the need for more up-to-date centiles for birthweight for gestational age.</p
Etiology and Clinical Characterization of Respiratory Virus Infections in Adult Patients Attending an Emergency Department in Beijing
BACKGROUND: Acute respiratory tract infections (ARTIs) represent a serious global health burden. To date, few reports have addressed the prevalence of respiratory viruses (RVs) in adults with ARTIs attending an emergency department (ED). Therefore, the potential impact of respiratory virus infections on such patients remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: To determine the epidemiological and clinical profiles of common and recently discovered respiratory viruses in adults with ARTIs attending an ED in Beijing, a 1-year consecutive study was conducted from May, 2010, to April, 2011. Nose and throat swab samples from 416 ARTI patients were checked for 13 respiratory viruses using multiple reverse transcription polymerase chain reaction(RT-PCR) assays for common respiratory viruses, including influenza viruses (Flu) A, B, and adenoviruses (ADVs), picornaviruses (PICs), respiratory syncytial virus (RSV), parainfluenza viruses (PIVs) 1-3, combined with real-time RT-PCR for human metapneumovirus (HMPV) and human coronaviruses (HCoVs, -OC43, -229E, -NL63, and -HKU1). Viral pathogens were detected in 52.88% (220/416) of patient samples, and 7.21% (30/416) of patients tested positive for more than one virus. PICs (17.79%) were the dominant agents detected, followed by FluA (16.11%), HCoVs (11.78%), and ADV (11.30%). HMPV, PIVs, and FluB were also detected (<3%), but not RSV. The total prevalence and the dominant virus infections detected differed significantly between ours and a previous report. Co-infection rates were high for HCoV-229E (12/39, 30.76%), PIC (22/74, 29.73%), ADV (12/47, 25.53%) and FluA (15/67, 22.39%). Different patterns of clinical symptoms were associated with different respiratory viruses. CONCLUSIONS: The pattern of RV involvement in adults with ARTIs attending an ED in China differs from that previously reported. The high prevalence of viruses (PIC, FluA, HCoVs and ADV) reported here strongly highlight the need for the development of safe and effective therapeutic approaches for these viruses
HIF-1 Modulates Dietary Restriction-Mediated Lifespan Extension via IRE-1 in Caenorhabditis elegans
Dietary restriction (DR) extends lifespan in various species and also slows the onset of age-related diseases. Previous studies from flies and yeast have demonstrated that the target of rapamycin (TOR) pathway is essential for longevity phenotypes resulting from DR. TOR is a conserved protein kinase that regulates growth and metabolism in response to nutrients and growth factors. While some of the downstream targets of TOR have been implicated in regulating lifespan, it is still unclear whether additional targets of this pathway also modulate lifespan. It has been shown that the hypoxia inducible factor-1 (HIF-1) is one of the targets of the TOR pathway in mammalian cells. HIF-1 is a transcription factor complex that plays key roles in oxygen homeostasis, tumor formation, glucose metabolism, cell survival, and inflammatory response. Here, we describe a novel role for HIF-1 in modulating lifespan extension by DR in Caenorhabditis elegans. We find that HIF-1 deficiency results in extended lifespan, which overlaps with that by inhibition of the RSKS-1/S6 kinase, a key component of the TOR pathway. Using a modified DR method based on variation of bacterial food concentrations on solid agar plates, we find that HIF-1 modulates longevity in a nutrient-dependent manner. The hif-1 loss-of-function mutant extends lifespan under rich nutrient conditions but fails to show lifespan extension under DR. Conversely, a mutation in egl-9, which increases HIF-1 activity, diminishes the lifespan extension under DR. This deficiency is rescued by tissue-specific expression of egl-9 in specific neurons and muscles. Increased lifespan by hif-1 or DR is dependent on the endoplasmic reticulum (ER) stress regulator inositol-requiring protein-1 (IRE-1) and is associated with lower levels of ER stress. Therefore, our results demonstrate a tissue-specific role for HIF-1 in the lifespan extension by DR involving the IRE-1 ER stress pathway
Ecology and Seasonal Habitat Use Patterns of Columbian Sharp-Tailed Grouse in Northern Utah
Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus: hereafter sharp-tailed grouse) populations have been declining. These declines have been attributed to a number of factors, including habitat loss due to agriculture, habitat fragmentation, overgrazing by livestock, and the loss to fire. To gather information about their status in northern Utah, I radio-marked sharp-tailed grouse in 2003 (n=15) and 2004 (n=20) in two research areas. The study areas were located on the south end of Cache County and in eastern Box Elder County. In the Cache study area, I monitored 7 males and 1 female in 2003, and 6 males and 3 females in 2004. In the Box Elder study area, I monitored 6 males in 2003 and 6 males and 5 females in 2004. I then located the radio-marked sharp-tailed grouse using telemetry and collected Visual Obstruction Readings (VOR) and vegetation data on each flush site and on a randomly selected paired point. I completed an unsupervised classification of the two study areas to determine if habitats were used more than would be expected based on availability. I then used a paired point linear regression to determine if vegetation parameters were correlated with sharp-tailed grouse on the landscape. Sagebrush in the Box Elder County study area and forbs in the Cache County study area were significantly correlated with habitat use by sharp-tailed grouse. The VOR readings were higher at the flush sites than at the paired points. The unsupervised classification showed that in Box Elder County, sagebrush was used in greater proportion than is available, while in the Cache County study area there were no habitat types that were used in greater proportion than was available on the landscape. I collected information on nest sites, nest success, broods, and mortality of these 2 populations. Nest success was 75% combined over the 2-year study, and mortality was 72% for both populations over the 2 years. Seasonal habitat use and distance travelled were determined using Global Positioning System points collected at every flush point. The distance traveled ranged from 0.9 km to 14.7 km, with the longest distance being travelled in the winter
Rödingen i Rostujåvri
Sveriges nordligaste rödingvatten av betydelse, Rostujåvri (RÄstojaure), har under drygt ett halvt sekel utgjort ett av landets i sÀrklass förnÀmsta sportfiskeomrÄden för storvuxen röding och harr. Sjön Àr 3 531 hektar stor, grund, och avvattnas bÄde vÀsterut till Atlanten och österut till Bottenviken.
I mitten av 1960-talet konstaterades redan i de kommersiella fÄngsterna och en serie provfisken att sjöns fisksamhÀlle hade skiftat över frÄn dominans av röding till dominans av harr. I augusti 2003 resulterade ett standardiserat provfiske med översiktsnÀt i en fÄngst bestÄende av 80,2 % harr, 12,3 % öring, 4,9 % lake men bara 2,6 % röding mÀtt i vikt. BÄde yrkesfiske och tidigt sportfiske riktat mot röding tycks ha bidragit till ett skifte i balansen av fiskarter, men rödingens Äldersstruktur antydde Àven ett klimatstyrt sÀsongsbetonat habitatskifte. Analys av fiskbestÄndens demografi, tillvÀxt, nÀringsval och parasiter avslöjade ett fisksamhÀlle som dominerades ekologiskt och numerÀrt av snabbvÀxande bottenlevande harr, kraftigt gynnad av ökad sommartemperatur i norra Sverige, och en serie upprepade rika Ärsklasser under Är med lÄg nederbörd och varma somrar. Medan storvuxen harr, lake och öring övergick frÄn en diet av bottendjur till fisk, uppvisade resterna av ett ungt och smÄvuxet rödingbestÄnd en nÀringsnisch begrÀnsad till djurplankton i ett mycket snÀvt, pelagiskt livsutrymme.
Eftersom inga könsmogna rödingar fÄngades i mitten av augusti antogs vuxna rödingar ha undflytt förhöjda vattentemperaturer, konkurrens och predation frÄn andra vÀrmegynnade fiskarter genom att vandra nedströms. Prover frÄn samernas isfiske med nÀt i maj 2004 avslöjade att de i augusti 2003 saknade Äldersgrupperna av röding Äter fanns pÄ plats i Rostujåvri vÄren dÀrpÄ. Otoliterna som utnyttjas för Älderanalyserna uppvisade fr.o.m. den tredje sommaren mönster av minskad tillvÀxt vilket tolkats som korresponderande tecken pÄ habitatskiften till en miljö med lÀgre temperatur. Sannolikt har ökad temperatur gynnat harrbestÄndet och intensifierat konkurrensen mellan harr och röding vilket lett till bÄde kortsiktiga och lÄngsiktiga svÄrigheter för rödingbestÄndet. Den inledande studien föreslÄr dÀrför ytterligare undersökningar i sjön sÄvÀl som nedströms i utloppen under andra perioder pÄ Äret
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